A pet or companion animal is an animal kept for companionship and enjoyment, as opposed to livestock, laboratory animals, working animals or sport animals, which are kept for economic reasons. The most popular pets are noted for their loyal or playful characteristics, for their attractive appearance, or for their song. Pets also generally seem to provide their owners with non-trivial health benefits; keeping pets has been shown to help relieve stress. There is now a medically-approved class of "therapy animals," mostly dogs, who are brought to visit confined humans. Walking a dog can provide both the owner and the dog with exercise, fresh air, and social interaction.

Koko the gorilla is one of few examples of a non-human animal which has had an explicit pet. Using sign language, she requested a cat; her first pet was a kitten named All Ball, to which she was reported to be quite attached and mourned for several days after the cat escaped and was killed by a car.

Contents

While in theory any animal might be a pet, in practice only a small number of species of mammals (especially dogs and cats) and other small animals, such as birds, fish, or lizards, are practical. One reason for this is that large animals are not able to fit inside small dwellings.

In general, a pet must either be small enough (or easily controlled) for his or her undesirable behavioral tendencies to be negligible, or the animal must be actually domesticable. Examples of the former are such animals as fish (including carnivorous ones such as piranha), chickens, invertebrates or small mammals.

A few animals are sufficiently capable of adapting to human interaction to be considered domesticable. Dogs ("man's best friend") are considered to be a classic example of domesticated animals normally suited to being pets. Domestic dogs are quite similar to wolves, but their physical form and behavior are characteristically different, more than mere differences in size, coat, or coloring. Behaviorally speaking, characteristic changes in dogs due to domestication include a prolonged infancy, increased playfulness, and increased barking. Wolves are far less playful and vocal.

Such animals as reptiles are typically considered exotic pets. This may change in the future, as 'exotic' pet ownership is increasing rapidly. Some of these animals, such as green iguanas, large monitor lizards, and large birds, do not make suitable pets for the average person, as they require extensive housing and diet. They can also become quite aggressive if not regularly handled. Exotic mammals are also becoming increasingly more popular as pets. For example, the domesticated hedgehog has been selectively bred to the point where its physical characteristics no longer directly match its wild European and African counterparts.[How to reference and link to summary or text]
One reads occasional reports in People and other magazines of individuals who have run into legal trouble for keeping large exotic pets, both in rural estates and urban apartments. A few years ago, New York Police Department officers arrested a man who had kept large cats and an alligator in a small Manhattan apartment [4]
Many animal species are difficult to handle and cannot be pets for the general populace. Raptors, such as eagles and falcons, must be handled very carefully to avoid attacks on their handlers; the sport of falconry is to a large extent ways of avoiding such outcomes, and so they are not really pets in the sense meant here. Large cats cannot become pets, as they do not reliably restrain their impulses (although cheetahs are an exception and have been kept as pets in the past). Nor do the large bears, for similar reasons. Small monkeys can be human companions, but they are notoriously unable to defer their curiosity which leads to much destruction. Several of the ferret and otter varieties can be human companions. Raccoons also fit this example. They adapt easily to almost any environment, but resist domestication.

A pet can be acquired from an animal shelter, a breeder, and from private transactions, typically due to the giving away of extra newborns after the birth of a litter. See also pet adoption. Because of environmental and public safety concerns, some pets are illegal in many areas.

The two most popular pets in most Western countries have been cats and dogs. In the United States, a 2007-2008 survey shows that dog-owning households outnumber those owning cats, but that the number of pet cats is higher than dogs.[6][7] Combined reptiles are the next popular followed by birds followed by horses, and finally, monkeys.

Animal protection advocates call attention to the pet overpopulation "crisis" in the United States. According to the Humane Society of the United States, 3-4 million dogs and cats are euthanized each year in the country and many more are confined to cages in shelters. This crisis is created by nonneutered animals (spayed/castrated) reproducing and people intentionally breeding animals. A particularly problematic combination of economic hardship combined with a love of animals contributes to this problem in parts of the rural United States.[8] In an average year, a fertile cat can produce three litters of kittens, with up to 4 to 6 kittens in each litter. Based on these numbers, one female cat and her offspring could produce up to 420,000 cats over a seven year period if not spayed or castrated. There are also major overpopulation problems with other pet species, such as birds and rabbits. Local humane societies, SPCAs, and other animal protection organizations urge people to neuter their pets and to adopt animals from animal shelters instead of purchasing them from breeders or pet stores.

Pets have the ability to stimulate their caregivers, in particular the elderly, giving people someone to take care of, someone to exercise with, and someone to help them heal from a physically or psychologically troubled past.[9] Having a pet may help people achieve health goals, such as lowered blood pressure, or mental goals, such as decreased stress.[10] There appears to be strong evidence that having a pet can help a person lead a longer, healthier life. In a study of 92 people hospitalized for coronary ailments, within a year, 11 of the 29 without pets had died, but only 3 of the 52 who had pets.[9]

Even pet owners residing in a long-term care facility, such as a hospice or nursing home, experience health benefits from pets. Pets for nursing homes are chosen based on the size of the pet, the amount of care that the breed needs, and the population and size of the care institution.[9] Appropriate pets go through a screening process and, if it is a dog, additional training programs to become a therapy dog.[11]

Different pets require varying amouns of attention and care; for example, cats have lower maintenance requirements than dogs.[12]

Some people with allergies can have adverse reactions to animal dander and fur or feathers. Some people with asthma can have attacks triggered by these. However, research supports that people who have been exposed to dogs and cats as pets from an early age may develop an immunoresistance to these allergens.[1]